Christians Under Attack

"Preliminary investigations show that the motivation behind the attack could have been revenge," the official said, adding that the owner had frequent disputes with local residents.

The official had initially said the killings were the result of a drive-by shooting.

Police, who swiftly cordoned off the area, found 15 revolver shell casings at the scene, the official said.

Cairo's Zeitoun district is a famed pilgrimage site where, according to witness accounts, the Virgin Mary appeared above the Church of Saint Mary over a period of several years in the late 1960s.

The apparitions were seen by millions including Copts, Muslims, Jews and atheists.

Egypt's Copts -- the largest Christian community in the Middle East -- account for an estimated six to 10 percent of the country's 76 million inhabitants and complain of systematic discrimination and harassment.